EP0506516A1 - Combustion air control device for turbomachine combustor - Google Patents

Abstract

The invention relates to a combustion chamber of a turbo machine comprising: a combustion enclosure (4) delimited by a wall (3); a peripheral enclosure (5) surrounding the combustion enclosure (4) and containing a pressurised oxygen carrier; and, a plurality of oxygen carrier inlet orifices (12) passing through the said wall and establishing communication between the peripheral enclosure and the combustion enclosure. <??>According to the invention, at least one of the said orifices (12) is associated with a sleeve (14); which passes through it; which communicates with the peripheral enclosure (5) via an outflow aperture device (36); and which has a pivoting shaft (16) around which it is mounted so as to be steerable; the outflow aperture device (36) being asymmetric with respect to the said pivoting shaft (16). <??>One application is the production of a gas turbine having a large range of operating regimes. <IMAGE>

Description

Modern turbo-machines are designed to operate at very different speeds between idle and full load. It appeared necessary to regulate the flow of oxidant admitted into the combustion chamber: FR-A-2 028 599 describes several variants of devices for adjusting the oxidant flow.

The invention relates to a device for adjusting the oxidant flow rate which is both simple and precise.

The subject of the invention is therefore a combustion chamber of a turbo-machine comprising: a combustion chamber, which is delimited by a wall and inside which combustion of a fuel is carried out; a peripheral enclosure, which surrounds said combustion enclosure and which is capable of containing an oxidizer under pressure; and, a plurality of oxidant intake orifices which pass through said wall and which are capable of establishing communication between the peripheral enclosure and the combustion enclosure.

According to the invention, at least one of said oxidant intake orifices is associated with a sleeve; which passes through it and is adjusted to it; which commnicates with the peripheral enclosure by an inlet opening device and with the combustion enclosure by a delivery opening device, the inside of the sleeve providing mutual communication between said inlet opening devices and repression; and which has a pivot axis about which it is pivotally mounted; however, that at least one of said inlet and outlet opening devices is asymmetrical with respect to said pivot axis.

• le dispositif d'ouvertures de refoulement du manchon comporte une coupe dudit manchon par un plan incliné par rapport audit axe de pivotement ;
• le dispositif d'ouvertures d'admission du manchon comporte un orifice traversant la paroi du manchon, non symétrique par rapport audit axe de pivotement ;
• le dispositif d'ouvertures d'admission comporte un volet réglable susceptible de former diaphragme ;
• la chambre de combustion comporte plusieurs manchons munis d'orifices d'admission de comburant, cependant que chaque manchon est attelé à un organe de réglage de son pivotement et que les divers organes de réglage de pivotement desdits manchons sont reliés à un dispositif unique de commande.

The following advantageous arrangements are also preferably adopted:

• the device for discharging openings of the sleeve comprises a section of said sleeve by a plane inclined with respect to said pivot axis;
• the sleeve inlet opening device has an orifice passing through the wall of the sleeve, which is not symmetrical with respect to to said pivot axis;
• the intake opening device comprises an adjustable flap capable of forming a diaphragm;
• the combustion chamber comprises several sleeves provided with oxidant inlet orifices, while each sleeve is coupled to a member for adjusting its pivoting and that the various pivoting adjusting members for said sleeves are connected to a single control device .

The main advantage of the invention lies in the modulation of the distribution of the air flow in the different orifices of the flame tube, depending on the speed, by means of mobile elements which is the solution offering the most potential gains. on the different performances. It makes it possible to adjust the richness and the residence time in the primary zone according to the thermodynamic conditions, in order to be placed as close as possible to the optimal operating point.

The invention will be better understood, and secondary characteristics and their advantages will appear during the description of embodiments given below by way of example.

It is understood that the description and the drawings are given for information only and are not limitative

• la figure 1 est une coupe axiale d'une chambre de combustion conforme à l'invention ;
• les figures 2 et 3 sont des coupes axiales agrandies du détail A de la figure 1, représenté dans deux configurations distinctes ;
• les figures 4 et 5 sont des coupes axiales analogues à celles des figures 2 et 3, d'une autre réalisation conforme à l'invention, également représentée dans deux configurations distinctes de fonctionnement, respectivement ; et
• la figure 6 est une coupe axiale, analogue à celle de la figure 2, d'une troisième réalisation conforme à l'invention.

Reference will be made to the appended drawings in which:

• Figure 1 is an axial section of a combustion chamber according to the invention;
• Figures 2 and 3 are enlarged axial sections of detail A of Figure 1, shown in two separate configurations;
• Figures 4 and 5 are axial sections similar to those of Figures 2 and 3, of another embodiment according to the invention, also shown in two separate operating configurations, respectively; and
• Figure 6 is an axial section, similar to that of Figure 2, of a third embodiment according to the invention.

The combustion chamber of FIG. 1 is of the annular type, of axis 1, and comprises an internal wall 2 and an external wall 3, which define between them the combustion chamber 4, as well as a casing 5, inside which said combustion chamber 4 is contained, this casing 5 being itself delimited by an internal envelope 6 and by an external envelope 7 .

Conventionally, the combustion chamber 4 is provided, at one of its ends, with a fuel injection device 8 combined with a device 9 for admitting primary oxidizer, and comprises, at its other end , an orifice 10 for discharging the burnt gases. The casing 5 also contains, during the operation of the combustion chamber, a compressed oxidizer, such as compressed air, coming from a source of compressed oxidizer symbolized by the arrow F, generally constituted by an air compressor. .

The internal 2 and external 3 walls are traversed by orifices 11 for additional oxidant intake, connecting the casing 5 to the combustion chamber 4, orifices 11 for admission of secondary oxidant and / or dilution. Other orifices 12 also establish communication between the casing 5 and the combustion chamber 4 and will more particularly be described below.

The orifice 12 in FIGS. 2 and 3 crosses the external wall 3 which has an opening 13 for this purpose.

A cylindrical duct 14 has a first transverse end shaped as a flange 15 perpendicular to the axis 16 of said duct 14, comprising an opening 26, and a second transverse end, contained in a plane P inclined relative to the axis 16 of the casing 14 and therefore comprising, seen in section, a sort of spout 17, and an opening 36. A plate 18, forming a support washer, is screwed (19) to the outside face of the internal wall 3 and has an orifice 20. A tubular section 21 has its internal wall 22 adjusted and made integral with the external face 23 of the cylindrical conduit 14; has its outer wall 24 rotatably mounted inside the orifice 20 of the plate 18; and is provided with a transverse flange 25, perpendicular to the axis 16 of the cylindrical conduit 14.

After assembly, all of the cylindrical conduit 14 and the tubular section 21 is rotatably mounted, practically without play, relative to the orifice 20 of the plate 18, that is to say, also, relative to the outer wall 3; and, the edge of the opening 13 of said external wall 3 are disposed between the plate 18 and the flange 25 of the tubular section 21, practically without play. Thus, the cylindrical conduit 14, and its internal spout 17, are orientable around axis 16.

When the nozzle 17 is located upstream of the axis 16 with respect to the direction of flow H of the gases inside the combustion chamber 4, the compressed oxidizer passes through the orifice 12 along the arrow J and arrives in the combustion chamber 4 substantially in the same direction as the arrow H (Figure 2).

On the contrary, when the spout 17 is located downstream from the axis 16 with respect to the direction of flow H of the gases, the compressed oxidizer passes through the orifice 12 arriving inside the combustion chamber 4 according to the arrow K, substantially counter-current with respect to the direction of arrow H (FIG. 3).

The embodiment of Figures 4 and 5 is similar to that of Figures 2 and 3 except the following feature: the cylindrical duct 14 is extended, beyond the flange 15, outside of the combustion chamber 4, by a section 27, the end of which constitutes a bottom 28 for closing off this section, and the cylindrical wall of which is crossed by an orifice 29 for communication of the casing 5 with the interior 12 of the section 27 and of the conduit 14.

The compressed oxidizer is admitted into the casing 5 according to a flow of direction L (substantially parallel to the direction H of gas flow inside the combustion chamber 4) and passes through the orifice 12 of the duct 14, either according to the arrow M (FIG. 4), on the one hand, by penetrating inside the orifice 12, passing directly through the orifice 29 located, like the spout 17, upstream from the axis 16 relative to the direction H of gas flow, on the other hand, arriving inside the combustion chamber 4 substantially in the same direction as direction H, ie according to arrow N (FIG. 5), on the one hand , bypassing the wall of the section 27 to penetrate inside the orifice 12 by crossing the orifice? 9, arranged this time downstream of the axis 16 with respect to the direction of flow H, on the other hand, by penetrating inside the combustion chamber 4 against the direction of direction H.
As a variant to this embodiment, the spout 17 may be on the side opposite to the orifice 29.

Finally, in the context of an embodiment similar to that of FIGS. 4 and 5, with or without spout 17, a jacket for adjusting the flow rate passing through the orifice 12 may be provided. The embodiment of Figure 6, similar to that of Figure 4 but free of spout 17, includes such a jacket.

In this embodiment, the tubular section 21 extends beyond the plate 18 to near an external transverse rim 31 extending the bottom 28 of the section 27. The tubular section 21 has an orifice 32 permanently disposed opposite the orifice 29 of the tubular section 27. The jacket 30 has an orifice 33 which can be arranged opposite the orifices 29 and 32. This jacket can on the other hand be oriented around the axis 16, by means of a lever 34, which is integral with it and which passes through a lumen 35 formed in the wall of the section 27 and opposite to the orifice 32, and partially, or even completely, block the orifices 32 and 29 in certain embodiments. Thus, a device for adjusting the the value of the flow rate passing through the orifice 12, which is added to the possibility of orienting the assembly of the duct 14, the tubular section 21 and the jacket 30 around the axis 16. As already indicated, the realization of figure 6 is c ompatible with the addition of a spout at the internal end of the duct 14, similar to the spout 17 of Figures 2 and 3, and, 4 and 5.

It also goes without saying that the rotation controls of the various cylindrical conduits 14 are advantageously coupled, for example by means of individual rack and pinion systems, to a single motor device for adjusting the rotations of all the conduits 14 simultaneously. Similarly, a single motor device for adjusting the orientations of all the liners 30 of the embodiment according to FIG. 6 is simultaneously coupled to the various levers 34 for adjusting the orientation of said liners and allows simultaneous adjustments of the oxidant flow rates passing through. the holes 12.

The embodiment shown in FIGS. 2 and 3 makes it possible to modify the direction of introduction (arrows J or K) of the oxidizer admitted into the combustion chamber 4 relative to the direction H of general flow of gases inside said combustion chamber 4. The transit time of the oxidizer is therefore adjustable by this means, this adjustment being useful to enable satisfactory operation to be obtained at very different gaits, previously almost incompatible, such as those of operations at full load and in slow motion.

The embodiment shown in Figures 4 and 5 already benefits from the same mode of adjustment as the previous one. In addition, the asymmetry of the position of the orifice 29 with respect to the axis 16 makes it possible either to benefit (FIG. 4) from the kinetic energy of the flow of oxidant admitted into the casing 5 in the direction L, and admit the oxidizer into combustion chamber 4 according to arrow M, on the one hand parallel to the direction H, on the other hand under a relatively high pressure, sum of the static pressure of the oxidant and the transformation into pressure of its energy kinetic, or (Figure 5) not to benefit from the kinetic energy of the oxidant admitted into the casing 5, and further to admit the oxidant into the combustion chamber 4 in the direction of the arrow N substantially opposite to that of arrow H.

The gradient for adjusting the transit time of the gases inside the combustion chamber 4 is increased compared to that obtained with the embodiment of FIGS. 2 and 3.

The embodiment of FIG. 6 also makes it possible to adjust the value at the flow rate of oxidant admitted into the combustion chamber 4. It is recalled that this solution is moreover compatible with those providing for a spout 17 (FIGS. 2 to 5) to the internal end of the cylindrical duct 14.

The invention is not limited to the embodiments described, but on the contrary covers all the variants which could be made to them without departing from their scope or their spirit.

Claims (5)

Turbo-machine combustion chamber comprising: - a combustion chamber (4), which is delimited by a wall (2-3) and inside which the combustion of a fuel is carried out; - A peripheral enclosure (5), which surrounds said combustion enclosure (4) and which is capable of containing an oxidizer under pressure; and, - A plurality of orifices (12) for admitting oxidizer, which pass through said wall and which are capable of establishing communication between the peripheral enclosure (5) and the combustion enclosure (4); characterized in that at least one of said oxidant inlet orifices (12) is associated with a sleeve (14); which passes through it and is adjusted to it; which communicates with the peripheral enclosure (5) by an intake opening device (26; 29) and with the combustion enclosure (4) by a discharge opening device (36), the interior ( 12) of the sleeve carrying out the mutual communication of said inlet and outlet opening devices; and which has a pivot axis (16) around which it is pivotally mounted; however, that at least one of said inlet and outlet opening devices is asymmetrical with respect to said pivot axis (16). Combustion chamber according to claim 1, characterized in that the sleeve opening device (14) comprises a section (36) of said sleeve by a plane (P) inclined relative to said pivot axis (16). Combustion chamber according to either of Claims 1 and 2, characterized in that the device for the inlet openings of the sleeve has an orifice (29) passing through the wall of the sleeve (14), which is not symmetrical with respect to said axis of pivot (16). Combustion chamber according to any one of Claims 1 to 3, characterized in that the intake opening device comprises an adjustable flap (30) likely to form a diaphragm. Combustion chamber according to any one of Claims 1 to 4, characterized in that it comprises several sleeves (14) provided with oxidant inlet orifices, however each sleeve is coupled to a member for adjusting its pivoting and that the various pivoting adjustment members of said sleeves are connected to a single control device.

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